maint: Clean up m-files to follow Octave coding conventions. Try to trim long lines to < 80 chars. Use '##' for single line comments. Use '(...)' around tests for if/elseif/switch/while. Abut cell indexing operator '{' next to variable. Abut array indexing operator '(' next to variable. Use space between negation operator '!' and following expression. Use two newlines between endfunction and start of %!test or %!demo code. Remove unnecessary parens grouping between short-circuit operators. Remove stray extra spaces (typos) between variables and assignment operators. Remove stray extra spaces from ends of lines.

--- a/scripts/strings/base2dec.m
+++ b/scripts/strings/base2dec.m
@@ -122,10 +122,10 @@
 %!assert (base2dec ("-1", 2), NaN)
 %!assert (base2dec ({"A1", "1A"}, 16), [161; 26])
 
-%% Bug #35621
+## Bug #35621
 %!assert (base2dec (["0"; "1"], 2), [0; 1])
 
-%%Test input validation
+## Test input validation
 %!error base2dec ()
 %!error base2dec ("11120")
 %!error base2dec ("11120", 3, 4)